/**
* Extended find interface used in situations where the implementator may or may not be able to
* answer the complete query. It will attempt to answer the pattern but if its answers are not
* known to be complete then it will also pass the request on to the nested Finder to append more
* results.
*
* @param pattern a TriplePattern to be matched against the data
* @param continuation either a Finder or a normal Graph which will be asked for additional match
* results if the implementor may not have completely satisfied the query.
*/
@Override
public ExtendedIterator<Triple> findWithContinuation(TriplePattern pattern, Finder continuation) {
if (graph == null) return new NullIterator<Triple>();
if (continuation == null) {
return graph.find(pattern.asTripleMatch());
} else {
return graph.find(pattern.asTripleMatch()).andThen(continuation.find(pattern));
}
}
/**
* Returns a collection of RDFStatements that match the described subject
*
* @param subject Subject
* @return collection of RDFStatements
*/
public Collection<RDFStatement> getStatements(String subject) {
if (subject == null || subject.isEmpty()) {
return null;
}
List<RDFStatement> statement = null;
try {
// define a describe query
String query = String.format("DESCRIBE %s FROM < %s >", subject, this.graphName);
logger.debug("Query: \n{}", query);
Query sparqlQuery = QueryFactory.create(query);
VirtuosoQueryExecution vqe = VirtuosoQueryExecutionFactory.create(sparqlQuery, this.graph);
// execute the query and get the graph
Model model = vqe.execDescribe();
Graph queriedGraph = model.getGraph();
// itreate over the retrieved triples, and place them inside a list
ExtendedIterator<Triple> iter = queriedGraph.find(Node.ANY, Node.ANY, Node.ANY);
statement = new ArrayList<>();
while (iter.hasNext()) {
Triple t = (Triple) iter.next();
RDFStatement stmt =
new RDFStatement(
t.getSubject().toString(), t.getPredicate().toString(), t.getObject().toString());
statement.add(stmt);
}
} catch (Exception ex) {
logger.error("Exception occured while querying for statements", ex);
}
return statement;
}
@Override
public void addGraph(Node gn, Graph g) {
// Convert to quads.
// super.addGraph(gn, g) ;
ExtendedIterator<Triple> iter = g.find(Node.ANY, Node.ANY, Node.ANY);
for (; iter.hasNext(); ) {
Triple t = iter.next();
add(gn, t.getSubject(), t.getPredicate(), t.getObject());
}
}
public static void removeAll(Graph g, Node s, Node p, Node o) {
ExtendedIterator<Triple> it = g.find(s, p, o);
try {
while (it.hasNext()) {
Triple t = it.next();
g.delete(t);
it.remove();
}
} finally {
it.close();
}
}
public static Collection<Node> containerMembers(Graph graph, Node container, Node containerType) {
if (!isContainer(graph, container, containerType)) return null;
ExtendedIterator<Triple> iter = graph.find(container, Node.ANY, Node.ANY);
SortedMap<Integer, Node> triples = new TreeMap<Integer, Node>(order);
try {
for (; iter.hasNext(); ) {
Triple t = iter.next();
int index = getIndex(t);
if (index == NOT_FOUND) continue;
// Insert
triples.put(new Integer(index), t.getObject());
}
} finally {
iter.close();
}
return triples.values();
}
@Override
public void delete(Graph g) {
Model[] model = separateStatementsWithBlankNodes(g);
deleteModel(model[1] /*statements without blank nodes*/);
// replace blank nodes in remaining statements with variables
StringBuffer patternBuff = new StringBuffer();
Iterator<Triple> tripIt = g.find(null, null, null);
while (tripIt.hasNext()) {
Triple t = tripIt.next();
patternBuff.append(SparqlGraph.sparqlNodeDelete(t.getSubject(), null));
patternBuff.append(" ");
patternBuff.append(SparqlGraph.sparqlNodeDelete(t.getPredicate(), null));
patternBuff.append(" ");
patternBuff.append(SparqlGraph.sparqlNodeDelete(t.getObject(), null));
patternBuff.append(" .\n");
}
StringBuffer queryBuff = new StringBuffer();
String graphURI = graph.getGraphURI();
queryBuff.append(
"DELETE { " + ((graphURI != null) ? "GRAPH <" + graphURI + "> { " : "") + " \n");
queryBuff.append(patternBuff);
if (graphURI != null) {
queryBuff.append(" } \n");
}
queryBuff.append("} WHERE { \n");
if (graphURI != null) {
queryBuff.append(" GRAPH <" + graphURI + "> { \n");
}
queryBuff.append(patternBuff);
if (graphURI != null) {
queryBuff.append(" } \n");
}
queryBuff.append("} \n");
log.debug(queryBuff.toString());
graph.executeUpdate(queryBuff.toString());
}
private static int countContainerMember(
Graph graph, Node container, Node containerType, Node member, boolean stopEarly) {
if (graph == null) {
Log.warn(GraphContainerUtils.class, "containerMember called with null graph");
return 0;
}
if (container == null) {
Log.warn(GraphContainerUtils.class, "containerMember called with null list");
return 0;
}
if (member == null) {
Log.warn(GraphContainerUtils.class, "containerMember called with null member");
return 0;
}
if (!isContainer(graph, container, containerType)) return 0;
int count = 0;
ExtendedIterator<Triple> iter = graph.find(container, Node.ANY, member);
try {
for (; iter.hasNext(); ) {
Triple t = iter.next();
Node p = t.getPredicate();
String u = p.getURI();
if (u.matches(membershipPattern)) {
count++;
if (stopEarly) return count;
}
}
} finally {
iter.close();
}
return count;
}
/**
* Basic pattern lookup interface.
*
* @param pattern a TriplePattern to be matched against the data
* @return a ClosableIterator over all Triples in the data set that match the pattern
*/
@Override
public ExtendedIterator<Triple> find(TriplePattern pattern) {
if (graph == null) return new NullIterator<Triple>();
return graph.find(pattern.asTripleMatch());
}
public static ExtendedIterator predicatesFor(Graph g, Node s, Node o) {
Set predicates = CollectionFactory.createHashedSet();
ClosableIterator it = g.find(s, Node.ANY, o);
while (it.hasNext()) predicates.add(((Triple) it.next()).getPredicate());
return WrappedIterator.createNoRemove(predicates.iterator());
}
public static ExtendedIterator subjectsFor(Graph g, Node p, Node o) {
Set objects = CollectionFactory.createHashedSet();
ClosableIterator it = g.find(Node.ANY, p, o);
while (it.hasNext()) objects.add(((Triple) it.next()).getSubject());
return WrappedIterator.createNoRemove(objects.iterator());
}
